The present disclosure relates generally to health monitoring, and in particular to Structural Health Monitoring baseline deviation assessments.
Structural Health Monitoring (SHM) systems have been utilized for the detection and characterization of damage within structures. For example, acousto-ultrasonic SHM techniques involve the interrogation of structures to identify damage by inducing vibrations within the structural material and monitoring the vibrational response. Such damage, often defined as changes to the material and/or geometric properties of a structural system which negatively impact the performance of the system, can be detected based on comparisons of the vibrational response of the structure in multiple states. For example, a structure is often first interrogated when the structure is in a known, defect-free condition, to establish a baseline vibrational response. Results of subsequent acousto-ultrasonic interrogations are compared to the baseline response to identify changes in the structure that may indicate damage.
Vibrational response of the structure is dependent upon environmental variables, such as temperature, mechanical strain, or other such variables. For instance, increased temperature of a structure results in expansion of the structural material and a corresponding change in the vibrational response of the structure to the acousto-ultrasonic interrogation. Comparison of interrogation results taken under the same or similar conditions can enable accurate damage assessments of the structure. Comparison of interrogation results at different conditions (e.g., temperatures, strains, etc.) can produce inaccurate damage assessments, thereby reducing the dependability, reliability, and effectiveness of the SHM system.